Alarm sound not making sound after the Lollipop update when on mute
Alarm not ringing after Lollipop update if choose Do Not Disturb mode ON.
When you choose "None" for your interruption settings, Nothing Comes Through. And that includes Alarms.
How to fix
Use the Priority only Mode, That lets you whitelist what comes through, and alarms are always whitelisted.
1. Do Not Disturb ON
No Interruptions, not even alarms
2. Priority only Mode
Allow certain features to interrupt when priority only.
Alarms always have priority.